Internal aquarium heater with bimetallic thermostat - also includes thermal cut=out switch with sensor in max. heat transfer region

摘要

The heater comprises an electric heating element (3) positioned within a glass tube (1), together with a bimetallic thermostat. The glass tube (1) also contains a safety cut-out switch (17) responsive to a given temp. threshold and with a sensor (24) which lies within the max. heat transfer region between the heating element (3) and the squarium water. Pref. the sensor (24) for the cut-out switch (17) lies in direct contact with the inside surface of the glass tube (1) and has a cross-section which matches the internal contour of the latter. The free end of the sensor (24) is bent inwards towards the heating element (3) and this bent end (25) is supported by an insulating block (26) from the latter. The free space within the glass tube (1) between the heating element (3) and the sensor (24) and the cut-out switch (17) is pref. filled with quartz sand.